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Friday, 8 June 2012

Deep Sea Dandelion

Image: NOAA Ship Okeanos ExplorerThermopalia taraxaca, I think

KABOOM!

It looks like a spaceship got shot down but it's actually an amazingly strange relative of the jellyfish.
I think the one above may well be Thermopalia taraxaca, spotted at hydrothermal vents near the Galápagos Islands at depths of 2,500 m (8,200 ft). It's a siphonophore, and with a main body some 4 cm (1.6 in) tall, a tiny one.

Like other siphonophores it's actually a whole colony of tiny creatures, each one known as a zooid, and all working together for mutual benefit. The feeding zooids look like those tiny dandelion petals and, I presume, feed on equally tiny crustaceans and such that can be found around the vents.

The world's foremost siphonophore is of course the Portuguese Man o' War. Like this most illustrious relative, the Deep Sea Dandelion has a pneumatophore at the top which lets them float. The difference is that the Deep Sea Dandelion also uses tentacles to tether itself to the sea floor. It's like a hot air balloon that doesn't want to drift too far.

It also has nectophores, which are muscular zooids who devote their lives to enabling the colony to swim.

Image: NOAA MBARIDromalia alexandri

Another Deep Sea Dandelion is the sensuously named Dromalia alexandri, which was pictured at a depth of 1,850 m (6.070 ft). That's about everything I know about it, though they appear to do the same "tentacle tethering" thing once they've found a nice place to stay.

So long as that nice place isn't right in the middle of the lawn, they're welcome to it.